The term automation equipment is understood to mean a device that runs a control program for influencing a process that has to be controlled. Equipments of this type are frequently referred to as SPC (Stored-Program Control), PLC (Programmable Logic Controller or just Controller for short), Soft SPC or Soft PLC. An automation equipment can be constructed in a modular manner and contain a programmable central processing unit and also intelligent modules, which take over individual automation functions such as weighing, axis control, regulation, etc. For the purposes of connection to a network, which is used for exchanging data with further components of an automation network, for example network components or field devices, an additional module, which is referred to as a communication processor, can be provided.
The term field device refers to a device that can be arranged locally in the field, that is to say in an automation network in the vicinity of the process that has to be controlled, and that performs functions for capturing process variables and/or influencing the process. Devices of this type are frequently also referred to as measurement transducer, sensor, positioner or actuator. They usually possess facilities for connecting to a network and utilize communication mechanisms from the world of automation for communicating. Examples of communication mechanisms of this type based on Ethernet comprise PROFINET, Ethernet IP, and Modbus TCP. A communication mechanism is defined by means of the associated protocol, which is usually standardized, and the underlying communication relation. Communication relations organize the communication between the devices taking part in the data transmission within the network, which are also referred to as users. Examples of communication relations comprise Client/Server, Master/Slave, Master/Master, Producer/Consumer and Publisher/Subscriber. In the case of Ethernet-based networks, TCP/IP is frequently used as the communication protocol.
The so-called network components are used to construct the network infrastructure. They are transparent to the other components of the automation network, for example to automation equipments and field devices, that is to say messages from said equipments and devices pass through the network components without process-related changes being performed on them. Network components do not exert any influence on the process sequence themselves. Since network components for Ethernet-based networks were initially deployed in the office environment, communication mechanisms from the office environment have been used up to now for monitoring and controlling the network. In the office environment, networks are usually monitored with a network management system. The communication between the network components and a network management station is frequently implemented with SNMP (Simple Network Management Protocol), a protocol that has no relevance to process control and that automation equipments typically do not recognize. This type of monitoring and control of the network therefore runs independently of the process management of the automation equipments. A direct and rapid reaction of an automation equipment to problems in the network is therefore not possible.
A method for monitoring and controlling a network is known from US 2002/0116486 A1 in which a monitoring device with communication mechanisms based on the OPC standard (Object linking and embedding for Process Control) is deployed. This standard is frequently applied in the world of automation for communicating. In a client/server relation, the monitoring device seizes data of other devices that are located in the network and that utilize the SNMP protocol customary in the office environment. As a client, the monitoring device is connected to a gateway that converts the SNMP objects into OPC objects. The method has the disadvantage that the communication between the SNMP server and the OPC client has to run via an additional facility.